Flexible couplings

ABSTRACT

A flexible coupling including a first hub having an inner face, a flexible insert having a plurality of exterior lobes and a plurality of interior lobes, a retainer ring having an interior which engages the exterior lobes of the flexible insert, and a second hub having an exterior surface contoured to engage the interior lobes of the flexible insert.

CONTINUING APPLICATION DATA

This application is a continuation-in-part of the application Ser. No.10/911,311 of Anthony L. Hauck filed Aug. 4, 2004, and entitled“Flexible Couplings” which is a continuation-in-part of U.S. applicationSer. No. 10/107,285 filed Mar. 26, 2002, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention set forth in this specification pertains to new andimproved flexible couplings and, more particularly, to such couplingshaving advantageous features of both shear and compression stylecouplings.

2. Description of Related Art

Flexible couplings have long been used for the purpose of transmittingrotation from one shaft to another. Such couplings are normally used inorder to accommodate comparatively minor shaft alignment problems suchas are occasionally encountered because of manufacturing or assemblyerrors. Because of the fact that these devices are widely used and havebeen known and used for many years, many different types of flexiblecouplings have been proposed, built, and used.

Certain particular flexible couplings have been manufactured in the pastso as to include two hubs or hub elements which are adapted to beconnected to the shafts joined by the coupling. These hubs are eachprovided with extending lugs, teeth, or ribs serving as holding means soas to be engaged by corresponding projections on a band-like orbelt-like motion transmitting means in order to cause the hubs to rotatein synchronism as one of the shafts is rotated. The bands or belts usedin these prior couplings have been flexible, somewhat resilient beltscapable of being wrapped around the hubs so that the projections on themengage the holding means on the hubs.

A metal band or ring is typically used to retain the belt in positionwrapped around the hubs. The interior of the band is shaped anddimensioned so that the band may be slid axially relative to the hubsduring the assembly and disassembly of the coupling so that the bandfits over the belt when the coupling is assembled so as to conformclosely to the exterior of the belt.

Some coupling designs have provided a pair of oppositely-disposed axialgrooves in the outer surface of the belt and a pair ofoppositely-disposed pins in the inner surface of the metal band. Thepins are located so as to slide into the grooves as the metal band isinstalled along a line parallel to the axis of rotation of the hubs. Thepins thus position the band and provide a degree of retention. However,if the shafts are grossly misaligned, the metal band will “walk-off” thebelt, causing the coupling to come apart. The axial grooves have alsobeen provided with an enlarged central portion such that the pins mustbe forced through the entrance of the axial groove and then “pop” intoplace in the central portion to give a tactile indication that the metalband is properly positioned with respect to the flexible belt.

In our U.S. Pat. Nos. 6,024,644 and 5,738,585, we have disclosedimproved “lock-on” apparatus for improving the retention of theaforementioned metal retainer bands. This improved apparatus employs anaxial groove for initially receiving a pin located on the underside ofthe metal retainer band and a circumferential groove opening into theaxial groove and into which the retainer band pin may be rotated. In theembodiments illustrated in the referenced applications, the axial grooveis bisected by a radial line which also bisects one of the lobes orprojections of the flexible belt. The circumferential groove isrelatively short, typically having been selected to be two times thewidth of the retainer ring pin. In practice, such apparatus must contendwith vibrations, harmonics, rotation, misalignment and various stressesand forces on the component parts.

SUMMARY

The following is a summary of various aspects and advantages realizableaccording to various embodiments of the invention. It is provided as anintroduction to assist those skilled in the art to more rapidlyassimilate the detailed design discussion which ensues and does not andis not intended in any way to limit the scope of the claims which areappended hereto in order to particularly point out the invention.

Accordingly, disclosed hereafter is a flexible coupling including afirst hub having an inner face and a flexible insert having a pluralityof exterior lobes and a plurality of interior lobes. A retainer ring isprovided having an interior which engages the exterior lobes of thefirst hub, while a second hub has an exterior surface contoured toengage the interior lobes. The exterior and interior lobes may each havea rounded contour formed between two flat faces, which facilitatestorque transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

An illustrative and presently preferred embodiment of the invention willnow be described in detail in conjunction with the drawings of which:

FIG. 1 is an exploded perspective of a coupling according to a preferredembodiment;

FIG. 2 is a side view of the coupling of FIG. 1;

FIG. 3 is a perspective end view illustrating a hub, insert and retainercomponents in assembled relation;

FIG. 4 is a perspective view of the coupling in the assembled state;

FIG. 5 is a side cross sectional view of the coupling in the assembledstate.

FIG. 5A is an enlarged view of a portion of the embodiment of FIG. 5.

FIG. 6 is a side cross sectional view of an embodiment according to theinvention;

FIG. 7 is a side cross section view of an embodiment according to theinvention;

FIG. 7A is a side cross-section view of the embodiment of FIG. 7 showinghub 13 moved axially away from hub 17.

FIG. 8 is a cross section view of an alternate embodiment;

FIG. 9 is an enlarged view of a portion of the embodiment of FIG. 8;

FIG. 10 is a side view of an alternate embodiment;

FIG. 11 is a perspective view of the embodiment of FIG. 10; and

FIG. 12 is a perspective view of an alternate embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The coupling of the illustrative embodiment includes a first hub 13, aflexible insert 15, a second hub 17 and a retainer member 19. The firsthub 13 includes an interior bore 22, a first cylindrical segment 21 anda mounting flange 23 having a circular outer edge 25. The face 27 of theflange 23 has a number of mounting holes 29 therein, each of which liesequally spaced on a circle of lesser diameter than that of the outeredge 25. Conventional fastening devices such as screws 28 may be used tosecure the hubs to respective shafts.

The insert 15 is preferably fabricated from a flexible material such as,for example, a suitable urethane, and may be split so as to facilitate“wraparound” installation The outer surface 31 of the insert 15 featuresa number of equally spaced exterior lobes 33, 34 35, 36, 37, 38projecting therefrom. The lobes, e.g., 33, are formed about equallyspaced radii extending from the center of the insert 15. The interiorsurface of the insert 15 features a number of interiorly projectinglobes 52, 53, 54, 55, 56, 57, which, in the embodiment of FIG. 1,alternate with the exterior lobes 33, 34, etc. In other words, as oneproceeds about the circumference of the insert 15 one encounters a firstexterior lobe 33, then an interior lobe 52, then a second exterior lobe34, then a second interior lobe 53, etc.

The second hub 17 includes a cylindrical segment 43 and aninsert-mounting segment or portion 45. The insert-mounting portion 45includes a number of wells or receptacles 47 which are shaped anddimensioned to mate snugly with the interior lobes, e.g., 52, 53, of theinsert 15. The hub 17 is preferably machined as a unitary part from asingle piece of metal stock, but of course could be constructed invarious other fashions. The second hub 17 further includes an interiorbore 44, typically of circular cross section dimensioned to receive ashaft of cooperating apparatus.

The interior 49 of the retainer 19 is specially contoured, shaped anddimensioned to receive and snugly mate with the exterior lobes, e.g.,33, 34, of the insert 15 when the coupling is in the assembled state.The retainer 19 has a first face 61 (FIG. 1), which receives and passesthe insert 15 into mating position with the exterior lobes 33, 34, etc.,and a second face 63 (FIG. 1) which includes a depending edge or flangeportion 65, which prevents the insert 15 from passing through theretainer 19, i.e., holds the insert 15 in a position wherein the insert15 is preferably encased by the retainer 19.

In the embodiment illustrated, the width “W₁,” of the retainer and thewidth “W₂” of the insert are selected such that the face 71 of theinsert 15 lies flush with the edge of the first face 61 of the retainer19, such that both the insert's face 71 and the edge 61 lie adjacent theflange face 27 in the assembled state. Thus, in assembly, the retainer19 “captures” the insert 15 and is then attached to the first hub 13 viaa number of fastening devices such as threaded bolts 73.

As shown, for example, in FIG. 3, the width W₃ of the insert matingportion 45 of the second hub 17 is preferably selected such that itsinterior face 147 terminates slightly short of the face of the insert15. Thus, the second hub 17 does not protrude through the insert 15 orextend to a point where it might contact the flange face 27 of the firsthub 13.

In operation in the assembled state (FIG. 4), the insert is snuglyencased and transmits torque and absorbs minor misalignment withoutexerting axial thrusts on the cooperating shafts to which the first andsecond hubs 13, 17 are respectively attached. Thus, the insert 15 doesnot tend to exert forces on the hubs 13, 17 tending to move themparallel to the central axis 75 of rotation in typical applications.Such forces may cause a hub to move, for example, 15thousandths of aninch, which is undesirable or unacceptable in certain applications.

FIGS. 5-7 illustrate various design considerations according to apreferred embodiment of the invention. According to this illustratedembodiment, the insert 15 exhibits a constant shear section width d₁.Each exterior lobe, e.g., 33, has respective flat sides 81 having aselected length d₂ and a central portion 83 between the two flat sides81. The central portion 83 has a circular outer contour of radius R₁.Adjacent surfaces of the drive ring (retainer) 19 are dimensioned toconform to the shape of the exterior lobe, e.g., 33, for example, inincorporating flat sections, e.g. 85 adjacent the flat sides 81 of theouter lobes, the flat sections e.g., 85 having a length d₂₁. The widthd₃ of each exterior lobe is the same.

Similar to the exterior lobes, each interior lobe, e.g., 52, hasrespective flat sides 87 of equal width d₄ and a central circularportion 89 connecting those sides 87 and having a radius R₂. The cornerto corner width d₆ of each interior lobe, e.g., 52, is the same.Finally, the insert includes a split 101 in one of the outside lobes33-38 to provide for wraparound installation.

An illustrative dimensioning in inches for a coupling of the size underconsideration is as follows:

R₁=1.875

R₂=1.625

d₁=0.500

d₂=0.730

d₂₁=0.725

d₃=3.978

d₄=0.423

d₅=0.510 (flat section of hub wings)

d₆=3.325

R₃=0.100

R₄=0.100

R₄ and R₃ are respectively inside corner lobe radii and outside cornerhub wing radii implemented to resist tearing and cutting. As thoseskilled in the art will appreciate, the dimensioning of the variouswidths and radii illustrated in FIGS. 5-9, of course, varies, forexample, with application and size of a particular coupling.Accordingly, as those skilled in the art will further appreciate, forexample, the corner to corner width of the interior lobes and/or theexterior lobes need not all be the same dimension and the exterior lobeand interior lobe widths could be equal in various embodiments.

FIGS. 5A and 6 illustrate various clearances of interest with respect toa coupling according to embodiment of FIGS. 5-7. The clearance C₁ is theclearance between the flat sides 87 of the interior lobes, e.g., 52, andthe adjacent surfaces of the central hub 17. The clearances C₂ are theclearances between the flat side portions 81 of the exterior lobes,e.g., 33, and the adjacent flat portions of the retainer 19. Theclearances C₅ and C₆₀ are the clearances between the outer and innerdiameter of the exterior lobes, e.g., 33, and the retainer 19 and hub17, respectively. The clearances C₃ and C₄ are the clearances betweenthe outer and inner diameter of the interior lobes, e.g., 52, and theretainer 19 and hub 17, respectively. Illustrative values in inches forthese clearances for a coupling, in which the outside diameter of thering 19 is about 14.72 inches. are:

C₁=0.030

C₂=0.035

C₃=0.060

C₄=0.060

C₅=0.060

C₆₀=0.060

FIG. 7 illustrates additional dimensions of interest in an embodimentaccording to FIG. 5. In particular, dimension C₈ represents thethickness of that part 65 of the retainer 19 which overlaps the insert15. Dimension C₇ represents the clearance range between the opposingfaces of the driving and driven hubs 17, 13. The clearance C₆ representsthe distance by which the face of the driven hub 13 is set back from theface of the insert 15. Dimension C₉ represents the clearance between theside face of the insert 15 and the interior edge of the retainer ring19. Dimension C₁₀ represents the clearance range between the face of theinsert 15 and the rear faces 301 of the receptacles 47 of the drivinghub 17. Representative dimensions in inches for an illustrative couplingof the size under discussion are:

C₆=0.0200

C₇=0.090-0.310

C₈=0.5000

C₉=0.0200

C₁₀=0.0200-0.2700

Several observations may be made with respect to operation of thecouplings according to various embodiments disclosed herein. First, theflat side surfaces on the interior and exterior lobes facilitate torquetransmission. The coupling further provides free axial float,illustrated, for example, by clearance ranges C₇ and C₁₀ in FIG. 7, aswell as relatively wider width W₂ of the insert and relatively widerwings W₃ of the hub, for example, when compared to features of previouscouplings such as ATR Sales' “A” or “M” series. In particularapplications, the design enables the driving and driven shafts to bepositioned at greater distances from one another than previous designs.In such case, for example, greater thermal growth of shafts can beaccommodated than in previous systems.

FIG. 8 illustrates an alternate and improved insert 150 captured by anouter retainer member 190 and receiving a second hub 170. The insert 150features exterior lobes 133, 134, 135, etc. and interior lobes 152, 153,154, etc., which are generally disposed in the same fashion as therespective exterior and interior lobes of the insert 15 (e.g. FIG. 1)but which are contoured differently. In particular, each lobe 133, 134,135 has two equal-length straight or flat side segments, e.g., 201, 202,leading to respective segments 203, 204 of a common radius. Respectiveends of the two radiused segments are joined by a centralcircumferentially lying segment 205. The central segment 205 may beeither a straight or slightly curved. This construction provides alocking effect which positively locates the rotating parts under load tolimit twist and to increase torsional stiffness and stability. It isdesirable to provide as much flat side area, e.g. 201, as possiblebecause these areas provide the driving surfaces of the coupling, whilethe radiused corners 203, 204 provide resistance which assists inpreventing the exterior and interior lobes from coming out of theirrespective mounting wells when under stress of operation.

FIG. 9 provides an enlarged view of a portion of the coupling structureof FIG. 8. For the particular coupling illustrated, the space S₁ betweenthe side of each interior lobe, e.g. 152, and the adjacent side of eachspoke of the inner hub 170 may be, for example, 0.060 inches, while thespace S₂ between each side of each lobe, e.g. 133, and each adjacentface of the retainer 190 may be 0.035 inches, for a coupling where thesegments of the inner lobes of the insert lie tangent to a circle 13.652inches in diameter. The angle α between the flat or straight sides ofeach inner lobe is 60 degrees in the particular illustrative embodiment.Such dimensioning is of course illustrative and will vary with variousembodiments as discussed above. Additionally, it may be noted thatsmaller coupling sizes may not be ideally suited to the use of insertshaving the alternate design shown in FIGS. 8 and 9.

FIGS. 10 and 11 illustrate an alternate embodiment wherein an insert 250is split at three locations so as to form three separate insert sections161, 162, 163. The particular illustrated splits shown in thisillustrative embodiment are located at the mid-point (radial centerline)of a respective outer lobe, e.g. 152. Segmenting an insert 250 as shownin FIGS. 10 and 11 lowers the effects of hysteresis, permitting thesegmented insert 250 to run cooler and prolonging its life. While FIGS.10 and 11 illustrate an insert divided into three segments, more or lessthan three segments could be used in various embodiments.

FIG. 12 illustrates an alternative embodiment where two inserts 15 arearranged to be mounted adjacent one another on extended wings 218 of aninner or second hub 217. An axially lengthened retainer, 219 thencaptures the two inserts 15 and attaches to the face of another hub 13in the manner generally illustrated in FIG. 1. This design doublestorque handling capability without increasing the diameter of thecoupling, which proves useful in applications where space is limited.More than two adjacently mounted inserts may also be provided.

Couplings as disclosed above have the advantage of combiningadvantageous aspects of both shear and compression couplings. Inparticular, the disclosed couplings normally operate in compression,which prevents exertion of axial thrusts, but can still shear to protectequipment in the event of lock-up or overload, etc. An example is thecase of shredding apparatus used to shred recycled material.Occasionally, the material will include prohibited foreign objects whichcan lock the shredder. In such case, the insert of a coupling accordingto the disclosed design will shear rather than break the associatedequipment.

While the present invention has been described above in terms ofspecific embodiments, it is to be understood. that the invention is notlimited to the disclosed embodiments. The role of “driving” and “driverhubs” may be reversed and dimensioning adapted to particular sizes andconditions. Thus, the present invention is intended to cover variousmodifications and equivalent methods and structures included within thespirit and scope of the appended claims.

1. A coupling apparatus comprising: a first hub having an inner face; aflexible insert having a plurality of exterior lobes and a plurality ofinterior lobes; a retainer removably attachable to said first hub andhaving an interior shaped and dimensioned to snugly and slidably comeinto driving engagement with said plurality of exterior lobes as saidretainer and insert move into an overlapping relation with one anotheralong a central axis common to said retainer and said insert; and asecond hub having a portion thereof shaped and dimensioned to snuglyreceive and mate with said plurality of interior lobes.
 2. The couplingof claim 1 wherein said first hub has a cylindrical segment and whereinsaid face comprises the face of a flange formed on said cylindricalsegment, said retainer being removably attachable to said flange.
 3. Thecoupling of claim 1 wherein said exterior and interior lobes each have arounded contour symmetrically formed about respective radii of saidinsert.
 4. The coupling of claim 1 wherein at least one exterior lobecomprises a first flat face and a circular portion.
 5. The coupling ofclaim 4 wherein said at least one exterior lobe further comprises asecond flat face and wherein said circular portion lies between thefirst flat face and second flat face.
 6. The coupling of claim 5 whereinsaid first and second flat faces are of equal length.
 7. The coupling ofclaim 1 wherein least one interior lobe comprises a first flat face anda circular portion.
 8. The coupling of claim 7 wherein said at least oneinterior lobe comprises a second flat face and said circular portionlies between said first and second flat face.
 9. The apparatus of claim1 wherein a portion of said second hub lying adjacent the inner face ofsaid first hub comes into abutment with said insert at a point selectedto space a first inner face of said second hub a selected distance fromsaid inner face of said first hub, and wherein said second hub is freelymovable axially at least a selected distance away from said insert andthe inner face of said first hub thereby imparting free axial float tosaid second hub.
 10. The apparatus of claim 1 wherein said second hubincludes a cylindrical segment integrally formed with said portion. 11.The apparatus of claim 1 wherein said retainer includes a depending edgeportion which prevents the insert from passing through a side of theretainer.
 12. The apparatus of claim 1 wherein a width of the retainerand the axial width of the insert are selected such that said retainerencases said insert.
 13. The apparatus of claim 12 wherein duringassembly of the apparatus, the retainer captures the insert and is thenattached to the first hub.
 14. The apparatus of claim 13 wherein thewidth of an insert mating portion of the second hub is selected suchthat an interior face of said second hub terminates short of the firstface of the insert whereby the second hub does not protrude through theinsert to a point where it might contact the flange face of the firsthub.
 15. The apparatus of claim 1 wherein the insert exhibits a constantshear section width.
 16. The apparatus of claim 1 wherein each exteriorlobe has respective flat sides having a selected length and a centralportion lying between the two flat sides, which central portion has acircular outer contour of a selected radius.
 17. The apparatus of claim16 wherein each interior lobe has respective flat sides of equal widthand a central circular portion lying between the two flat sides, whichcentral portion has a circular outer contour of selected radius.
 18. Theapparatus of claim 17 wherein said interior lobes alternate with saidexterior lobes such that, as one proceeds about a circumference of saidinsert one encounters a first exterior lobe, then an interior lobe, thenan exterior lobe, then an interior lobe in repeating fashion.
 19. Theapparatus of claim 18 wherein each exterior lobe has the samecorner-to-corner width and wherein the corner-to-corner width of eachinterior lobe is the same.
 20. The apparatus of claim 1 wherein eachexterior lobe has the same corner-to-corner width.
 21. The apparatus ofclaim 1 wherein each interior lobe has respective flat sides of equalwidth and a central circular portion lying between the two flat sides,which central portion has a circular outer contour of selected radius.22. The apparatus of claim 1 wherein the corner-to-corner width of eachinterior lobe is the same.
 23. The apparatus of claim 1 wherein theinsert includes a split therein.
 24. The apparatus of claim 23 whereinsaid spilt is formed in one of said exterior lobes.
 25. The apparatus ofclaim 1 wherein said first hub is adapted to be attached to a rotatableshaft.
 26. The apparatus of claim 25 wherein said second hub is adaptedto be attached to a rotatable shaft.
 27. The apparatus of claim 1wherein said second hub is adapted to be attached to a rotatable shaft.28. The coupling apparatus comprising: a first hub for mounting to afirst shaft and having an inner face; a flexible solid plastic insertcomponent, which as a free standing component, has a plurality ofexterior lobes and a plurality of interior lobes formed thereon, saidinsert component further having first and second faces disposed aselected axial width apart; a second hub for mounting to a second shaftand having an exterior portion thereof shaped and dimensioned to engagethe interior lobes of said insert component; a retainer componentremovably attachable to said first hub and having an interior shaped anddimensioned to slidably receive and engage the exterior lobes of saidinsert; and a central opening in said retainer component sized such thatsaid second hub is passable therethrough to a position wherein saidexterior portion of said second hub engages said interior lobes and saidinterior portion of said retainer component engages said exterior lobes.29. The apparatus of claim 28 wherein said second hub includes acylindrical segment integrally formed with said exterior portion. 30.The apparatus of claim 28 wherein said retainer component includes adepending edge portion which prevents the insert from passing through aside of the retainer component.
 31. The apparatus of claim 28 wherein awidth of the retainer component and the axial width of the insert areselected such that said retainer component encases said insertcomponent.
 32. The apparatus of claim 31 wherein during assembly of theapparatus, the retainer component captures the insert component and isthen attached to the first hub.
 33. The apparatus of claim 32 whereinthe width of an insert mating portion of the second hub is selected suchthat an interior face of said second hub terminates short of the firstface of the insert component whereby the second hub does not protrudethrough the insert to a point where it might contact the inner face ofthe first hub.
 34. The apparatus of claim 28 wherein the insertcomponent exhibits a constant shear section width.
 35. The apparatus ofclaim 28 wherein each exterior lobe has respective flat sides having aselected length and a central portion lying between the two flat sides,which central portion has a circular outer contour of a selected radius.36. The apparatus of claim 35 wherein each exterior lobe has the samecorner-to-corner width.
 37. The apparatus of claim 28 wherein eachinterior lobe has respective flat sides of equal width and a centralcircular portion lying between the two flat sides, which central portionhas a circular outer contour of selected radius.
 38. The apparatus ofclaim 37 wherein the corner-to-corner width of each interior lobe is thesame.
 39. The apparatus of claim 28 wherein the insert includes a splitto provide for wraparound installation.
 40. The apparatus of claim 39wherein said split is formed in one of said exterior lobes.
 41. Theapparatus of claim 28 wherein a portion of said second hub lyingadjacent the inner face of said first hub comes into abutment with saidinsert at a point selected to space a first inner face of said secondhub a selected distance from said inner face of said first hub, andwherein said second hub is freely movable axially at least a selecteddistance away from said insert and the inner face of said first hubthereby imparting free axial float to said second hub.
 42. The couplingapparatus of claim 28 wherein the interior of said retainer componentcomes into driving engagement with said exterior lobes as it slidablyreceives said lobes.
 43. A coupling apparatus comprising: a first hubhaving an inner face; a flexible insert having a plurality of exteriorlobes and a plurality of interior lobes; a retainer removably attachableto said first hub and having an interior lobe receiving portion shapedand dimensioned to snugly and receive said plurality of exterior lobes;and a second hub having a lobe receiving portion thereof shaped anddimensioned to snugly receive and mate with said plurality of interiorlobes; said first hub, second hub, retainer and insert being alignablewith respect to one another along a common horizontal axis, said secondhub being moveable along said axis such that said lobe receiving portionenters the interior of said flexible insert and comes into engagementwith said interior lobes; said retainer being movable along said axissuch that said flexible insert enters the interior of said retainer andsaid exterior lobes come into engagement with said interior lobereceiving portion of said retainer; said retainer thereafter coming intoabutment with said inner face of said first hub.
 44. The coupling ofclaim 43 wherein said first hub has a cylindrical segment and whereinsaid face comprises the face of a flange formed on said cylindricalsegment, said retainer being removably attachable to said flange. 45.The coupling apparatus of claim 43 wherein said engagement between saidretainer and said exterior lobes comprises driving engagement.
 46. Thecoupling apparatus comprising: a first hub for mounting to a first shaftand having an inner face; a flexible solid plastic insert component,which as a free standing component, has a plurality of exterior lobesand a plurality of interior lobes formed thereon, said insert componentfurther having first and second faces disposed a selected axial widthapart; a second hub for mounting to a second shaft and having anexterior portion thereof shaped and dimensioned to receive and engagethe interior lobes of said insert component; and a retainer componentremovably attachable to said first hub and having an interior shaped anddimensioned to receive and engage the exterior lobes of said insert;said first hub, second hub, retainer and insert being alignable withrespect to one another along a common horizontal axis, said second hubbeing moveable along said axis such that said lobe receiving portionenters the interior of said flexible insert and comes into engagementwith said interior lobes; said retainer being movable along said axissuch that said flexible insert enters the interior of said retainer andsaid exterior lobes come into engagement with the interior lobereceiving portion of said retainer; said retainer thereafter coming intoabutment with said inner face of said first hub.
 47. The couplingapparatus of claim 46 wherein said engagement between said retainer andsaid exterior lobes comprises driving engagement.
 48. A four componentcoupling apparatus comprising; a first component comprising a first hubfor mounting to a first shaft and having an inner face; a secondcomponent comprising a flexible solid plastic insert component, which asa free standing component, has a plurality of exterior lobes and aplurality of interior lobes formed thereon, said insert componentfurther having first and second faces disposed a selected axial widthapart; a third component comprising a second hub for mounting to asecond shaft and having an exterior lobe receiving portion thereofshaped and dimensioned to engage the interior lobes of said insertcomponent; and a fourth component comprising a retainer componentadapted to removably attach to said first hub and having a centralopening including an interior lobe receiving portion shaped anddimensioned to slidably receive and engage the exterior lobes of saidinsert and to prevent said insert from passing through a first side ofsaid retainer component, said retainer component having an axial widthgreater than that of said insert; and said first hub, second hub,retainer and insert being alignable with respect to one another along acommon horizontal axis, said second hub being moveable along said axissuch that said lobe receiving portion enters the interior of saidflexible insert and comes into engagement with said interior lobes; saidretainer component being movable along said horizontal axis such thatsaid flexible insert enters the interior of said retainer component andsaid exterior lobes come into engagement with the interior lobereceiving portion of said retainer component; a second side of saidretainer component thereafter coming into abutment with said inner faceof said first hub; each of said plurality of exterior lobes of saidinsert including a solid semicircular portion; and each of saidplurality of interior lobes of said insert including a solidsemicircular portion.
 49. The apparatus of claim 48 wherein saidinterior lobes alternate with said exterior lobes such that, as oneproceeds about a circumference of said insert one encounters a firstexterior lobe, then an interior lobe, then an exterior lobe, then aninterior lobe in repeating fashion.
 50. The coupling apparatus of claim48 wherein said engagement between said retainer and said exterior lobescomprises driving engagement.
 51. The coupling apparatus comprising: afirst hub for mounting to a first shaft and having an inner face; aflexible solid plastic insert component, which as a free standingcomponent, has a plurality of exterior lobes and a plurality of interiorlobes formed thereon, said insert component further having first andsecond faces disposed a selected axial width apart; a retainer componentremovably attachable to said first hub and having an interior shaped anddimensioned to receive and engage the exterior lobes of said insert,said retainer component having a first open face through which saidinsert slidingly passes along an axis in a first direction into aposition wherein the interior of said retainer component engages saidexterior lobes, said retainer component having a second face and asurface portion which prevents said insert from passing through saidsecond face; and a second hub for mounting to a second shaft and havingfirst and second segments, the first segment being shaped anddimensioned to receive and engage the interior lobes of said insert andto cause said second segment to abut said insert at a point whichprevents said second hub from passing through said insert to a pointwhere said second hub comes into contact with the inner face of saidfirst hub.
 52. The coupling apparatus of claim 51 wherein said positioncomprises a position wherein the interior of said retainer drivinglyengages said exterior lobes.
 53. A coupling apparatus consisting of fourcomponents comprising; a first component comprising a first hub formounting to a first shaft and having an inner face; a second componentcomprising a flexible solid plastic insert component, which as a freestanding component, has a plurality of exterior lobes and a plurality ofinterior lobes formed thereon, said insert component further havingfirst and second faces disposed a selected axial width apart; a thirdcomponent comprising a second hub for mounting to a second shaft andhaving an exterior lobe receiving portion thereof shaped and dimensionedto engage the interior lobes of said insert component; and a fourthcomponent comprising a retainer component adapted to removably attach tosaid first hub and having a central opening including an interior lobereceiving portion shaped and dimensioned to slidably receive and engagethe exterior lobes of said insert and to prevent said insert frompassing through a first side of said retainer component, said retainercomponent having an axial width greater than that of said insert; andsaid first hub, second hub, retainer and insert being alignable withrespect to one another along a common horizontal axis, said second hubbeing moveable along said axis such that said lobe receiving portionenters the interior of said flexible insert and comes into engagementwith said interior lobes; said retainer component being movable alongsaid horizontal axis such that said flexible insert enters the interiorof said retainer component and said exterior lobes come into engagementwith the interior lobe receiving portion of said retainer component; asecond side of said retainer component thereafter coming into abutmentwith said inner face of said first hub.
 54. The coupling apparatus ofclaim 53 wherein: each of said plurality of exterior lobes of saidinsert includes a solid semicircular portion; and each of said pluralityof interior lobes of said insert includes a solid semicircular portion.